RE: ORA-XS-323-Q: Prepending Nodes

The issue we were addressing is better illustrated with this example:
  <a>
   <b1/>
   <b2/>
   <b3/>
    ...
   <xsl:attribute name="c"/>
  </a>
The performance hit is that the output cannot be streamed until
xsl:attribute is processed.

Regards,

Mark

________________________________
Mark V. Scardina     
Group Product Mgr & XML Evangelist
CORE & XML DEVELOPMENT 
Web Site: http://otn.oracle.com/tech/xml/
 
  



> -----Original Message-----
> From: Michael Kay [mailto:mhk@mhk.me.uk] 
> Sent: Tuesday, February 17, 2004 8:27 AM
> To: 'Mark Scardina'; public-qt-comments@w3.org
> Subject: RE: ORA-XS-323-Q: Prepending Nodes
> 
> 
> > SECTION 5.6.1: Constructing Complex Content
> > 
> > Item 1:
> > This subsection says that attribute nodes generated by
> > sequence constructor instructions are prepended to the result 
> > sequence. Such a sequence reordering could lead in some cases 
> > to serious performance degradation. Would not an acceptable 
> > alternative be to say that attribute nodes (if any) should be 
> > generated before any other nodes? 
> 
> I've tried hard to avoid using phrases that have any temporal 
> connotations, i.e. any suggestion that one thing is done 
> before doing another thing. I think you have read a temporal 
> meaning into the word "prepended" that wasn't intended. There 
> isn't actually a problem for
> implementations: if you say
> 
> <a b="c">
>   <d/>
> </a>
> 
> then the b="c" is evaluated first to produce a sequence X 
> containing an attribute node, the sequence constructor <d/> 
> is evaluated to produce a sequence Y containing an element 
> node, and the two sequences X and Y are concatenated (i.e. X 
> is prepended to Y). We should try to find a better way of 
> saying it, but finding the right words isn't easy. 
> 
> Michael Kay
> 
> 
>

Received on Thursday, 19 February 2004 02:34:42 UTC